Molding tray



Nov- 13, 1951 F. w. FULLER 2,574,915

' MOL-DING TRAY `Filed July 24, 1948 e w l@ Patented Nov. 13, 1,951

MOLDINGTRAY Frank W..,Fullcr, St. Paul, ;Minn., assignor to Rock Island Millwork Company, Rock Island, Ill., a vcorporation of Illinois Application July 24, 1948, Serial No. 40,514

1 The present invention relates to -themanufacture of hot-pressed boards, panels 'and the like,

and in particular to apparatus-involved.

In this eld a moldable 4composition is integrated in a. hot press tothe desired `form-commonly a flat panel. The mass -to due-molded is placed in a tray for entryintothepress, wherein the bottom ofthe vtray provides the-mold-surface for one panel face. The present invention-pertains to features Yof tray construction, and operations in combination lwithl other-elements.

It is an object offthe invention -to provide-a tray with a -movable portion for exposing lthe molded object therein lto .facilitate grasping and -removing it. Y

A `particular object of the inventionistheprovision of a tray having a-removableend walL-aj-nd a partially removable bottom, to expose almolded panel to facilitateAgrasping-it and VAremoving it planewise of the panel. i

It is a particular fobjectto proide atraywith a Vthin flexible sheetmetal bottom,-looseat one-end Aoi. a flat panel.

In the drawings:

Fig. `1 is a perspective view lof a suitable tray embodying the preferred features of construction in `which a removable'end wall lis. carried -by a movable portion `of -the ibottom -which latter drops away from the normalV position in a horizontal tray. v

Fig. 2 is a `viewin vertical cross-sectionof a tray in a hot press: to illustrate the formation of a flange for interlocking Lthe molded product to the tray, to illustrate a hold-down guide for the tray side walls, and toillustrate a yparticular construction of a punch -platen in the press which aids in the formation of the interlocking flange.

Fig. 3 is a more or less .diagrammatic view showing operation of the tray to facilitate grasping and removing a panel board.

Fig. 4 is a more or less diagrammatic View showing the filling of a trayand 4the function therein of a magnetic tray bottom.

It is to be understood that -theforegoing illustrations are merely exemplary of the presently 13 Claims.

vvenience, is directed to the Aformation -of flat :uct is available.

The invention is best explained by reference to the .molding of a substantially dry `mixture of wood sawdustand a suitable binder therefor, such as thermosetting resin, thoroughly distributed throughout the sawdust,.as for example, by. mixing with the sawdust .a Afinely divided powdered resin-forming material, for .which an appropriate phenol-formaldehyde condensation prod- Such a moldable mixture may be heated and pressed to integrate it into a sort of synthetic lumber or molded object, particularly a flat panel. `For example, such a Vmoldable mixture .is` placed at a substantially uniform depth and density into a .flat-bottom tray with retaining side walls for the mixture, and the tray is set on a hotplaten of a suitable press. Acompanion heated punch platen moves onto the top of the tray contents to heat and compress it, thereby to integrate the mass to a form which conforms to the spaces between the tray bottom and the punch platen. Thus, the vproblem of removing the molded form, `or panel, from the tray, is encountered, .and this problem vis enhanced when one or more side Walls of the tray are undercut, as will be hereinafter described. Such undercutting is desirable, so that the .formed product or panel willbe retained in and'by the tray as the punch platen is withdrawn, thereby to overcome any tendency of the molded body to follow the punch platen on withdrawal. According to thesurface of the punch platen face and the ycharacter of the mass to b e molded, there is a variable tendency for the board to stick to the` face. For example, where there is present on the platen a wire screen, the tendency to stick is great. Also, where the punch platen has projecting side plates as illustrated, there is a vtendency for molding around the edges thereof, when there are narrow clearance spaces adjacent the side plates.

In the tray of the present invention, such undercutting is purposely employed to retain the molded product in the tray, and additionally, means is provided to retain the tray against being lifted -by the board in the event it should stick to the punch platen as it is withdrawn.

As illustrated in the drawings, the undercutting is employed in two opposite parallel side walls of the tray, whereby it becomes possible to withdraw the molded product planewise of the product upon suitable removal of an end wall of the tray. Mere removal of an end wall does not `sufficiently expose the board to permit convenient engagement of it, involving contact with the molded bottom face thereof as 'by grasping the product to move it-endwise from the tray. Where the product is to be pulled-endwise from the tray, rather than pushed therefrom, as might be accomplished by moving the opposite end wall slidingly between the undercut side walls, a portion of the tray bottom is moved lto expose the bottom of vthe board for grasping it for such Withdrawal.

Onel-way to meet these problems is illustrated in Fig; 1 wherein an exemplary rectangular tray I is shown in perspective, with a bottom i I made of sheet metal, preferably iron or steel or other magnetic material, for a function later to be vde- Y scribed. The tray has two parallel side walls I2 and I3 and two end WallsA vIll and I5, which four walls in normal relation constitute a rectangular frame to hold on the tray the charge to be molded therein. Walls I2, I3 and I4, as shown, are preferably rigidly related in the form of a U- shaped structure of which the end opening of the U is adapted to receive the end wall I5 between the side walls I2 and I3. The bottom II is secured to the end vwall l and is' preferably Y unsecured to the side walls I2 and I3, at least for a considerable distance away from the open end of the U-structure so that the bottom may f drop away in part at least from the side walls I2 and I3, in a manner comparable to that illustrated. Preferably, the end wall I5 is secured to and carried by the dropping end ofthe bottom II in order that there is, in effect, but one moving part to open the tray.

lOne advantage of dropping the whole end of the tray bottom, rather than a limited kpart thereof, that is, a part only sufficiently for the purposes of grasping the board, and of doing so lby a flexible bottom member, is that the mold surface against which the board is formed is thereby a continuous surface, not likely to leave any record in the molded surface of any seam or joint in the tray bottom.

The greater thickness of the end wall I5 compared to th-e thickness of the end wall I4, results from use of the end wall I5 as a leading end in filling the tray with a charge from a hopper, as

Y illustrated in Fig. 4, which hopper has mecha- ,the position or supports for the tray permit the In Fig. 1, side walls I2 and I3 are undercut at I8 in a straight line groove about 1/8 inch deep, of which groove I8 in sidewall I2 is visible. Also, these side walls l2 and I3 have lateral projections IS and 20 forming corresponding shoulders of the side wan l2 has its projecting 'simmer on their outer vertical faces for co-action with guides or hold-down means'which function in the pressing operation, as will be explained in connection with Fig. 2. For moving the tray, the lateral projections I9 and 20 have'on their vertical outer faces rack teeth 2|, which engage driving pinions (not shown).

Fig. 2 represents, in fragmentary View, a crosssection of the filled tray I0 as it contains a product under final compression in the hot press. Numeral 25 d-esignates a platform platen of the press, which may be heated to a temperature in the range from 300 F. to 400 F., preferably 350 F. The lled tray is moved so that the bottom II rests on the platen 25. The side walls I2 and L I3 of the tray are suitably retained against outward movement under lateral pressure, and at the same time they are positioned against Vertical movement whichy might result through a tendency of the board to follow the upper platen as it is withdrawn. Accordingly, in the side Wall I2, the groove I8 effectsthe formation of a thin v,flange 26 on the molded product. The o uterface positioned against and under faces of a suitable guide and hold-down designated 21, which is recessed at 28 to receive the shoulder I9. Thus, the recess 28 provides vertical and horizontal positioning means for the side wall I2 of the tray. Corresponding parts function for opposite side Wall I3.

Numeral 30 represents a compressed panel board of which the moldable mixture before compression was originally present in the tray to the level designated by dotted line 3I flush with the top edges of the tray side walls I2, I3, I4 and i5. VFor example, a tray 2" deep is filled level to its #top with the moldable mixture, and the mixture is ultimately compressed to a board 1/4 thick. The undercut grove I8 is such as to form a retaining flange l26 about ik thick.

j Numeral 32 represents the upper press platen which, as a punch platen, moves onto the tray contents. It is preferably heated to the same temperature as the bottom platen 25. Platen 32 is carried by a foundation plate 33 which projects beyond the side walls of the punch platen 32; at least to a sucient extent to provide a backing yfor side plates all around the vertical extent of the punch platen 32, as illustrated by one such side plate 34, which tapers downwardly on the inside for drawing. As illustrated, foundation 33 may be the bottom platen of an adjacent upper opening in a multi-opening press. The side plates 34 are such as to form a rectangular body of size to fill the tray I0 by entering alongside the four side walls of the tray, with a clearance of about 1/8 inch all around. This space tends to be filled with an ultimate -vertical flange of irregular character. To facilitate clearance, the side walls may be slightly rounded from square form as indicated at 35 on tray side wall I2, and Aat 36 on the platen side plate 34. Plates 34 function to protect the in- -vner punch platenv 32r from wear and chipping, by use or accident, and for such purposes may be easily removed and replaced. Side plates 34 also ,function toprovide anchoring and fastening means for any desired element which maybe placed over the surface of the punch platen 32 for desired special effects on the molded prod- ,uct, for example, a wire screen. Additionally, the side plates 34 desirably project beyond the platen surface 32, thereby to form a dished platen area for the entire tray, which area thus constitutes a chamber to house or conserve steam which is created in the hot-pressing from any water or moisture in the mix, whether substantially dry or additionally wetted. The terminal edges 38 of the 'side plates 34 thus function to compress the charge under them to a greater density at the edges than at the center of the tray, Vand this greater compression forces additional material laterally into the recess I8 to form the retaining flange 26 for anchoring the molded sheet'into the tray.

Fig. 3 shows the tray of Fig. l as it may appear afterA leaving the press in Fig. 2. The tray is shown as having moved generally in the direction of arrow 40 from the press to the posiytion shown, on suitable tracks or guides 4I which support the tray bottom II in normal closed position. When it is desired to open the tray, suitable means operate for that purpose. Convenf-iently, this is accomplished by action of the weight of end Wall I5, which on droppin-g carmolded panel 30. Dropping is permitted .by

kport or grid functions for these purposes.

-tapering the supporting rails 4|, as shown by the ends designated 42.

l gether, the board-3D is exposed at both faces and may be grasped and pulled endwise from .the

tray. Mechanical grasping means are preferably employed, which resist-the temperature of the hot board, and which do -not damage the surfaces thereof. Rubber grip rolls are suitable, as indicated by rolls 44 vand 45, Arespectively, mounted on shafts 46 and 41. VThe shafts lland 41 may be powered to cause the rolls vto pull the board out of the tray planewise of the board, or they may merely exert gripping pressure through the rolls for bodily movement of the shafts in withdrawing the molded panel. v v In using thin bottoms of metal vvfor the tra I0, it tends to acquire a warped or irregular condition as a result of the constant heating, cooling, flexing, and handling thereof. It is important to flll the tray to a uniform depth corresponding to the height of the side walls. A warped tray bottom Il makes the depth irregular when 'the filling is flush to the top edges of the side walls.

Means is employed to avoid the 'effect of a warped bottom in filling the tray. Fig. 4 shows part of a hopper 50, the bottom of which has a feeding area 5l, capable of discharging fill material to a scrape-oiflevel, as the tray moves along in the direction of arrow 49 under; the hopper 50. This is preferably accomplishedrby means to raise portions of the bottom to normal tray level and simultaneously to draw portions of the tray down to normal level. When the tray bottom is magnetic, a horizontal magnetic sup- A series of magnets provides a platform or lgrid at the .normal tray level and substantially under the feeding zone 5l of thehopper 55,so that! when the tray is filled the depth is normal. Magnetic means is illustrated in the form of a grid of spaced bar form permanentmagnets 52 supported on cross bar 53. cated within a collecting hopper 54 into which material from hopper 55 may fall when no tray properly receives it. On the magnets 52 isa suitably thin non-magnetic` separator layer 55, to limit sliding friction of the tray over the magnets, yet to permit sufcient magnetic flux for the desired flattening of therbottor'n.`

The apparatus of the present invention is not limited to the size and proportions shown, nor to the illustrated relations ofthe parts. Numerous changes and modifications of the structure are contemplated as falling within the scope of the appended claims.

I claim: Y

1. A tray in which to mold a body from .abulk mass fill in the tray, comprising in normal position a rectangular plane bottom of flexible sheet material, parallel side walls, and two end walls joining said side walls, said walls together forming a frame around and above said bottom, Said bottom at one end of the tray being unsecured to said walls so as to flex away from said walls 2. A tray in which to mold a body from .a bulk f mass fill in the tray, comprising in normal posi-vu These are shown lo- `tion-arectangular plane bottomof flexible sheet material, `parallel side walls, and two end walls #joining said side walls, said walls together formvvingaaframearound and above said bottom, said side vwalls being undercut from the interior of j the tray along their entire length to form paral- `zlel molded flanges on said body, said bottom at one end of the tray being unsecured to said walls so as to fiexV away from said walls and being else- -where secured in normal fixed relation to said side walls, at least one of said end walls being -Icarri'ed by said flexing end of the bottom, whereby movement of said end wall out of normal position exposes an end of said molded body, whereby to facilitate grasping said molded body for removal from the tray by sliding said flanges in said undercut side walls.

3. A tray in which to mold a body from a bulk mass ll in the tray, comprising in normal position a rectangular plane bottom of exible magnetic sheet material, parallel side walls, and two end walls joining said side walls, said walls together forming a -frame around and above said bottom, said -bottom at one end of the tray being unsecured to said walls so as to flex away from said walls and being elsewhere secured in normal fixed relation to said side walls, at least one of said end walls being carried by said flexing end of the bottom, whereby movement of said end wall out of normal Aposition exposes an end of said molded body, whereby to facilitate grasping said molded body for removal from the tray.

4. A tray in which to mold a body from a bulk mass ll in the tray, comprising in normal position a rectangular plane bottom of flexible magnetic sheet material, parallel side walls, and two end walls joining said sidewalls, said walls together forming a frame around and above said bottom, said side walls being undercut from the interior of the tray along their entire length to form parallel molded flanges on said body, said bottom at one end of the tray-being unsecured to said walls so asto flex away from said walls and ybeing elsewhere secured in normal xed relation to said side walls, at least one of said end walls being carried by said exing end of the bottom, whereby movement of said end wall out of normal position exposes an end of said molded body, whereby to facilitate grasping said molded body for removal from the tray.

5. A tray in which to mold a body from a bulk mass fill in the tray, comprising in normal position a plane bottom of fiexible sheet material, two side walls, and two end walls joining said side walls, said walls together forming a frame around and above said bottom, said side walls and one end wall forming a generally U-shaped pocket from which `an interposed rigid mass may be withdrawn along the plane bottom, said bottom at the U-opening being unsecured to the adjacent e'nd portions of said side walls so as to Vhex away from said side walls and being elsewhere secured in normal xed relation to said side walls, at least the end wall atthe U-opening being removable from normal position, whereby movements of said end wall and said bottom out of normal positions expose an end of said molded body, whereby to facilitate grasping said molded body for removal from the tray.

6. A tray in which to mold a body from a bulk mass fill in the tray, comprising in normal position a bottom of flexible sheet material, two side fwalls,.and two end walls joining said side walls, ,said wallstogether forming a frame around and above said bottom, saidside walls andone .end

,ati/agie wall forming a generally U-shaped pocket from which an interposed rigid mass may be withdrawn generally in an endwise direction, said bottom at the U-opening being unsecured to the adjacent end portions of said side walls so as t0 flex away from said side walls and being elsewhere secured in normal lxed relation to said side walls, at least the end wall at the U-opening being removable from normal position, whereby movements of said end wall and said bottom `out of normal positions expose an end of said molded body, whereby to facilitate grasping said molded body for removal from the tray.

7. A tray in which to mold a body from a bulk mass illl in the tray, comprising in normal position a bottom having an end portion movable downwardly from normal position relative to a remaining portion in normal bottom position, two side walls, and two end walls joining said side walls, said walls together forming a frame around and above said bottom, said side Walls and one end wall formingr a generally U -shaped pocket from which an interposed rigid mass moldled in the tray may be withdrawn, said movable portion of the bottom at the U-opening being unsecured to the adjacent end portions of said side walls so as to move away from said side walls and being elsewhere secured in normal fixed relation to said side walls, at least the end wall at the U-opening being removable from normal position whereby movements of said end wall and said bottom portion out of normal positions expose an end of said molded body, whereby to facilitate grasping said molded body for removal from the tray.

8. A tray in which 'to mold a body from a' bulk mass fill in the tray, comprising in normal position a plane bottom of flexible sheet material, ,walls together forming a frame around and above said bottom, at least one portion ofA the frame being removable with respect to a remaining portion which latter forms an area from which interposed molded material on the bottom may be withdrawn slidingly on the bottom, the walls forming said area being undercut, said bottom at an area along one edge of the tray and at a removable frame portion being unsecuredk to said walls so as to flex away from said walls and being elsewhere secured in normal xed relation to walls, whereby removal of the removable frame portion out of'normal position and flexing of the bottom expose an edge and the bottom of said molded body, whereby to facilitate grasping said molded body for removal from the tray.

9. A tray in which to mold a body from a bulk mass fill in the tray, comprising in normal position a bottom having a portion movable from normal position with respect to the remainder in normal position, walls together forming a frame around and above said bottom, one portion of thes.;t

frame being removable with respect to a remain- .ing portion which latter forms an area from which interposed molded material on the bottom may be withdrawn slidingly on the bottom, the

walls forming said area being undercut, said bot-fj.

tom at an area along one edge of the tray and at a removable frame portion being unsecured to A said walls so as to move away from said walls and being elsewhere secured in normal fixed relation to walls, whereby removal of the removable frame portion out of normal position and move- 'ment or the movable portion of the bottom expose an edge and the bottom of said molded body. whereby to facilitate grasping said molded body for removal from the tray.

10. A tray in which ,to mold a body fromfa bulk mass ll therein comprising in molding pofrom said portions in flexing of the bottom along a flexing line therein extending between said side Walls, a portion at least of the bottom extending from said flexing line in the -direction toward the other end of said bottom being secured to said side walls.

11. A tray in which to mold a body from a bulk mass ll therein comprising in molding position a plane bottom of flexible sheet material, two end walls and two side walls together forming a rectangular retaining frame for said illl over said bottom, one end portion of the bottom being unsecured to the adjacent portions of the side walls and being movable downwardly away from said portions in flexing of the bottom along a flexing line therein extending between said side walls, the remaining portion of the bottom extending from said flexing line in the direction towardfthe other end of said bottom being secured to said v side walls and the, corresponding end wall.

.12. A tray in which to mold a body from a bulk mass fill therein comprising in molding position a plane bottom of flexible sheet material, two end walls and two side walls together forming a rectangular retaining frame for said ll over said bottom, one end wall being secured to the corresponding end portion of the bottom and being unsecured to the adjacent side walls. the said corresponding end portion of the bottom being unsecured to the 'adjacent portions of the side walls and being movable downwardly away from said portions in flexing of the bottom along ya flexing line therein extending between said side walls, a portion at least of the bottom extending from said flexing line in the direction toward the other end of said bottom being secured to said side walls.

13. A tray in which to mold a body from a bulk mass fill therein comprising in molding position a plane bottom of flexible sheet material, two end walls land two side walls together forming a rectangular retaining frame for said ll over said bottom, one end wall being secured to the corresponding end portion of the bottom and being unsecured to the adjacent side walls, the said'corresponding end portion of the bottom being unsecured to the adjacent portions of the side walls and being movable downwardly away from said portions in flexing of the bottom along a flexing line therein extending between said side walls, the remaining por- "tion of the bottom extending from said flexing line in the direction toward the other end of said bottom being secured to said side walls. f ,4

FRANK W. FULLER.

REFERENCES CITED -The following references are of record in the ille of this patent:

UNITED STATES PATENTS Number Name Date 1,116,669 Birdsey et al Nov. 10, 1914 A1,140,840 Moore May 25, 1915 1,731,240 Apfelbaum Oct. 15, 1929 2,269,557 Sexton Jan. 13, 1942 

